1. Field of the Invention
This invention relates to culvert directional flow control devices, and more particularly to an automatic culvert directional flow control device designed to prevent water from backing up against the normal desired flow of water through a drainage system.
2. Description of the related art
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is "prior art", or should be considered relevant for this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. .sctn.1.56(a) exists.
U.S. Pat. No. 2,541,665 issued to C. Prudhon and titled "Automatic Fan Damper" is directed to an electric fan with damper blades which are open by the air pressure and closed by gravity. The damper blades are carried on pivot rods which are slightly off vertical to allow the weight of the damper blades to act to close them.
U.S. Pat. No. 2,877,792 issued to F. Tybus and titled "Surge or Back Flow Valve" is directed to a valve designed for a vertical pipe with the flow of liquid going in an upward direction. The segments 23 and 24 are elevated into a position which allows water to flow through by the pressure of the water. When the pressure drops, gravity allows the segments to fall back into a horizontal position which retards the flow of water back down the pipe.
U.S. Pat. No. 3,166,093 issued to A. Hopper and titled "Check Valve" is directed to a support designed to carry very heavy check valves. The wing members pivot around the support member to allow fluid to flow in one direction and to prevent the flow of fluid in the opposite direction.
U.S. Pat. No. 3,179,164 issued to L. Heller et al and titled "Anti-icing Arrangements for Heat Exchangers of Air Condensing Apparatus" is directed to a valve with curved flaps which open downwardly with water pressure, and has counterweights to bias the flaps in the closed position. The valve is designed for vertical pipes.
U.S. Pat. No. 3,374,804 issued to O. Stegerud and titled "Check Valves" is directed to a valve for use in horizontal pipes. The valve flaps are mounted with its seating surface directed obliquely upwards so that the weight of the flaps is made effective in the direction of closure. The flaps are mounted in a side by side fashion.
U.S. Pat. No. 3,533,438 issued to S. Smith and titled "Island Check Valve" is directed to a check valve with spring biased vanes. The pressure of the water opens the vanes, and the springs close the vanes when the pressure drops enough.
U.S. Pat. No. 3,831,628 issued to E. Kintner and titled "Check Valve" is directed to a check valve using a rubber diaphragm. When the water pressure is great enough it will flex the diaphragm and the diaphragm halves will open. The resiliency and tendency of the rubber diaphragm to close will cause the diaphragm to close when the pressure drops below a predetermined fluid flow.